                 (+ x dx) (+ y dy)
                 (or looser c) 
                 (conj taken [x y])))
-      nil)))
+      )))
 
 (defn available-moves-at
   "Provides the list of moves that can be done from a cell"

(defn ^boolean is-cell-empty?
  "Indicates whether a cell is owned by any player"
  [cell]
  (or (= cell :empty) (= cell :wall)))

(defn available-cells-by-dir
  "Indicates the convertible cells when clicking at [x y], and returns:

         y (+ yi dy)
         looser nil
         taken []]
    (let [c (get-in board [x y])]
      (cond
        (is-cell-empty? c) nil ;; No move: reached end and only 1 type of cell
        (and looser (not= looser c)) {:winner c      ;; Who wins the cells
